Question

Write an answer to the Guiding Question:

How can some traits “skip" a generation?

write it like a 7th grader

Answer 1

How can some traits “skip” a generation?

Genes control traits. Each person has two versions of a gene (one from each parent). These versions are called alleles.

- Dominant allele: shows up even if you have just one copy. I’ll write it as A.
- Recessive allele: only shows up if you have two copies (one from each parent). I’ll write it as a.

If a parent has one dominant and one recessive allele (Aa), the dominant allele hides the recessive one. That parent looks like the dominant trait but still carries the recessive allele. We call that parent a carrier.

Example with attached earlobes (simple example for learning):
- A = free earlobes (dominant)
- a = attached earlobes (recessive)

If both parents are carriers (Aa and Aa), their children can be:
- 25% AA (free earlobes)
- 50% Aa (free earlobes, carriers)
- 25% aa (attached earlobes)

So the parents can both look like they have free earlobes, but one child can have attached earlobes. That looks like the trait “skipped” a generation because the parents didn’t show it but the kid did.

Other reasons traits seem to skip:
- Sex-linked traits (like some kinds of color blindness) can show up more in boys and seem to skip girls who are carriers.
- Some traits need environment or many genes, so they might not appear even if the genes are there.

In short: a trait “skips” a generation when parents carry a hidden (recessive) version of a gene but don’t show it, and their child gets two hidden copies and does show it.